A known way to unify fixed and mobile communications relies on the so called IP Multimedia Subsystem or IMS architecture. United States patent application US 2010/0111079 entitled “Method and Apparatus for Network Based Fixed Mobile Convergence” (Duffy et al.) for instance describes such a network based IMS solution wherein the calls from both SIP (Session Initiation Protocol) endpoints and non-SIP endpoints are handled by a single application server.
IMS however requires dedicated endpoints such as UMTS phones that support SIP, or requires adaptation of existing phones through software updates. The solution known from US 2010/0111079 for instance requires installation of a Network Based Fixed Mobile Convergence (NB-FMC) client on the mobile device, and installation of a NB-FMC Application Server to invoke network based FMC service features such as call request handling. Because the user has to buy a new terminal supporting certain protocols or upgrade his existing terminal, deployment of IMS based solutions is a slow process, and the market penetration is small.
United States Patent Application US 2009/0262733 entitled “Dynamic Call Anchoring” (Olson) discloses an alternative prior art solution based on call anchoring logic that enables to make a call from a mobile handset (152 in FIG. 4 of US 2009/0262733) and to anchor the outbound call at the user's PBX (IP PBX 164 in FIG. 4 of US 2009/0262733), e.g. in the private enterprise network, a home-based network or a VoIP network. The call anchoring logic (172, 168) needed thereto resides in the mobile handset, in the private network, or in a combination of the mobile handset and private network, as is mentioned in paragraph [0025] of US 2009/0262733. As a result, Olson also has to modify the mobile handset and/or the private network.
International Patent Application WO 2009/076971 entitled “A Method of and an Arrangement for Call Establishment Between an Internet Communication Environment and a Mobile Communication Environment” describes a solution to extend GSM service, or more generally mobile service, to the Internet cloud. By emulating the user's mobile device 2 in gateway 6 as an Internet client and maintaining in gateway 6 the binding between the user's mobile identity, i.e. the MSISDN, and the Internet user name, e.g. John Smith, the user can establish/receive calls on his mobile device 2 that are maximally routed over the Internet 4 for cost saving reasons. As is indicated on page 2, lines 12-23 of WO 2009/076971, the user maintains mobility while the possibility of making calls free of charge over the Internet is maximally exploited. In order to further optimize costs, the status of the mobile device is maintained by the gateway 6, i.e. status parameters of the mobile device that may influence the costs of terminating calls thereon are maintained, like an indication that the user equipment is a mobile device, the geographical location, a cost indication, availability and messaging capacity.
WO 2009/076971 only teaches to extract some cost-related status parameters of the mobile device in order to use these status parameters to cost-optimize termination of calls to/from the user. The system disclosed in WO 2009/076971 does not enable the user to experience the status and features of his preferred communication system, e.g. his PBX, on his mobile 2. The gateway 6 known from WO 2009/076971 simply has no connectivity to such a preferred communication system, and also does not suggest to extend certain Internet behavior to the mobile device. The gateway 6 known from WO 2009/076971 consequently does not enable the user to bi-directionally enjoy PBX behavior on his mobile device, like for instance a directory, busy line notification, voice mail, etc., and enjoy mobile system behavior on his VoIP phone, like for instance SMS service. More generally, WO 2009/076971 does not extend features and states of the user's preferred communication system to the user's mobile endpoint since its objective is merely to reduce communication costs, not to extend features and states.
United States Patent Application US 2007/0070976 entitled “Mobile and Packet-Based Call Control” (Mussman et al.) is considered to constitute the closest prior art solution. US 2007/0070976 describes the presence of a Network Convergence Gateway (NCG) in a mobile network for delivering calls destined to VoIP phones to the corresponding mobile terminal, i.e. the GSM phone of the same user, and for extending services provided in the fixed network to the mobile network.
The NCG known from US 2007/0070976 however acts as a conventional Mobile Switching Centre (MSC) and SS7 gateway that contains VLR (Visitor Location Register) and routing functionality as is indicated by paragraph [0079] of US 2007/0070976. This NCG consequently is a rather complex, expensive, GSM specific node.
Another drawback of the NCG known from US 2007/0070976 is that this NCG only extends incoming calls to the user's GSM terminal, and consequently does not expose behavior of the GSM terminal in the fixed network when outgoing calls are made from the GSM terminal. The known NCG in other words does not enable bi-directional endpoint abstraction as a result of which it fails to expose abstracted endpoint behavior (or even presence) in the fixed network.
It is an objective of the present invention to disclose an improved solution for exposing behavior of an abstracted endpoint in the user's communication system, like for instance an application server, a PBX, an IP Centrex, a cloud-based PBX system, etc. More particularly, it is an objective of the present invention to disclose a network abstraction gateway and a corresponding method for endpoint abstraction that is not tied or limited to one particular technology like GSM, that enables to expose the abstracted endpoint's behavior in bi-directional communication, i.e. inbound and outbound from the point of perspective of the abstracted endpoint, that does not require software upgrades of endpoints or buying new, dedicated endpoints that support for instance SIP, and that does not rely on a complex node like the above mentioned NCG from Mussman et al. integrating MSC, VLR and routing functionality.